1. Field of the Invention
The present invention relates to a vibration speaker contained in portable communication instruments such as a portable telephone or pager, which speaker performs not only sound function but also vibration function at the same time.
2. Description of the Prior Art
Generally speaker is sound-generating instrument that outputs sound signal received electrically and electronically or bell or melody inputted beforehand into sound hearable by man.
Such speaker is usually not only used as large size phonation media that greatly amplifies sound volume as being connected to audio system or amplifier but also used very much as small size phonation media as having been very much miniaturized.
Particularly speaker applied at small size communication instruments such as portable telephone or pager is usually called also microspeaker as size is formed innovatively small.
By the way, as small size communication instruments such as portable telephone or pager are becoming more and more miniaturized, microspeaker is also more and more miniaturized to adequately correspond to trend.
FIG. 1 shows an example of microspeaker mainly used in existing portable communication instruments which speaker is composed of largely case 1, magnet 2 contained in this case 1, voice coil 3 and vibration plate 4.
Speaker generates sound as voice coil 3 moves up and down owing to magnetic field formed by interaction between voice coil 3 and magnet 2 if high-frequency electric current is applied at voice coil 3 through lead wire from outside, whence vibration plate 4 where an end of voice coil 3 is attached vibrates finely.
To make a more detailed explanation, because high-frequency electric current applied at voice coil 3 through lead (wire) is alternating current, if magnetic field generated by voice coil 3 according to electric current applied at voice coil 3 is formed in same directionality with that formed according to magnet 2, voice coil 3 moves downward to magnet 2 side as attractive force is generated that attracts each other between magnet 2 and voice coil 3.
Contrarily if magnetic field generated by voice coil 3 according to electric current applied at voice coil 3 is formed in opposite directionality with that formed according to magnet 2, voice coil 3 is pushed upward from magnet 2 side as repulsive force is generated that pushes out each other between magnet 2 and voice coil 3.
As voice coil 3 goes up and down according to magnetic field variation applied at voice coil 3 as explained above, vibration plate 4 attached to voice coil 3 vibrates up and down which phenomenon is discharged outward so that sound is generated to perform phonation function.
On the other hand, vibration means is also made to be furnished at the same time together with the above speaker in portable communication instruments in aspect of care of ambiend people so that alarm may be felt not by sound but by vibration; whence the most often used vibration means is vibration motor.
But because recently there is essential need for miniaturization and slimmerization of communication instruments as described before, each part materials contained in these communication instruments must also correspond to it.
What is recently suggested for this is vibration speaker where vibration function is added to speaker, whose typical examples are reported in Japanese Published Official Patent Notices Heisei 10-14195, Heisei 10-117472 and Heisei 10-229596.
All those already applied for invention patent generate sound or induce vibration according to action by which high- or low-frequency electric current is selectively applied to voice coil 3 as shown in FIG. 2 to FIG. 4.
Namely sound is generated or vibration is induced according to frequency of electric current applied at voice coil 3 by way of vibration width. of vibration plate 4 where an end of voice coil 3 is attached in FIG. 2, while in FIG. 3 and FIG. 4, sound is generated by vibrating vibration plate 4 when electric current applied at voice coil 3 is high frequency but vibration is to be felt as vibration member 5 vibrates where magnet 2 is integrally attached so that this vibration is transmitted to outer case when low-frequency electric current is applied.
Magnetic field must be precisely considered which shall be generated at voice coil 3 in order to induce sound and vibration by making electric current to be inputted only at voice coil 3 as explained above.
Namely sound generation is lowered as vibration width is decreased as vibration plate 4 weight is increased where voice coil 3 is attached if coil winding number goes to be increased while the coil winding number should be large enough to increase electric current amount flowing at voice coil 3.
Contrarily vibration amount is decreased as vibration width of vibration member 5 is decreased that shall resonate when electric current is inputted if voice coil 3 winding number is reduced.
Therefore the above previous applied invention patents have demerit that vibration amount is decreased in relatively low frequency band and the output vibration sensitivity is not good because voice coil 3 is wound with reference to sound loudness according to vibration plate 4.
On the other hand this applicant has already proposed Korean Patent applications No. 98-22244, Nos. 98-23812 through 98-23815 and No. 98-22659 in order to solve the above disadvantage in which propositions this applicant has separately furnished coils where high- and low-frequency electric currents are inputted respectively.
Namely here high-frequency electric current to generate sound by oscillating the vibration plate is applied to voice coil attached at vibration plate while low-frequency electric current to generate vibration is applied to vibration coil separately furnished at vibration member bottom so that electric current supply (amount in low frequency band is maximized for vibration force to be maximized.
But in those prior applications there is a problem that the vibration amount is not made large enough to be sensed outside because the vibration induced by electric current applied to the vibration coil as a vibration member furnished upon the vibration coil exhibits a seesaw or rocking action.
Namely if vibration member is to be oscillated by seesaw action, vibration member will move in direction of mutual balance of both sides so that weight cannot be made of maximum utilization; and particularly action shaft at time of the seesaw action acts as vibration load so that it rather causes vibration volume reduction.
Main purpose of present invention is to maximize vibration quantity as vibration member is made feasible of resonation in vertical direction by individually furnishing signal input devices for sound generation and. vibration generation respectively.
This invention to achieve the above purpose comprises a case, a vibration plate in order to generate sound, the outside edge of which vibration plate is affixed to top part of the case, a cylinder-shaped voice coil whose top is fixedly connected to lower surface of the vibration plate, a vibration member where magnet and yoke is combined integrally, which magnet is polarized up and down at bottom of the voice coil, and which yoke constitutes magnetic circuit, having been attached to the above magnet, a vibration coil wound in single phase so as to resonate in up-and-down direction by interaction with the vibration member, which vibration coil is attached to bottom surface of the above case at bottom part of the vibration member connecting this vibration member with the case.